1. Field of the Invention
The present invention relates to an improved method for the determination of total organic carbon in aqueous solutions, and to apparatus useful for performance of said method. Particularly, the method of the present invention relates to oxidizing organic carbon present in aqueous solution to carbon dioxide, with subsequent detection of carbon dioxide for determination of total organic carbon originally present in said aqueous solution. The apparatus of the present invention comprises a cell within which the organic carbon species are oxidized, and related to detection apparatus.
2. Description of the Prior Art
The determination of organic carbon in aqueous solution is commonly performed for such purposes as controlling the amount of organic compounds present in recycle streams, and monitoring organic compound content of waste streams. Methods, and apparatus useful therein, for such organic carbon determination are well known in the art. For example, See U.S. Pat. No. 3,854,877, Casky et al; U.S. Pat. No. 3,964,868, DiCola et al; U.S. Pat. No. 3,955,924, Northmore et al; U.S. Pat. No. 3,958,941, Regan et al; and U.S. Pat. No. 3,607,071, Staffin et al.
U.S. Pat. No. 3,958,941 discloses a process, and equipment therefor, for determining organic carbon in aqueous mixture, wherein an organic sample introduced into a water stream circulating through a reaction cell is oxidized with air in the presence of an ultraviolet light source to form carbon dioxide. Such carbon dioxide, stripped from said circulating water stream, is dissolved in a second stream of water in a measuring chamber. Resistivity of water in the measuring chamber is measured, and this measurement is related to the amount of carbon originally introduced into said oxidation chamber. This process requires air as a source of oxygen for oxidizing carbon present and stripping carbon dioxide from water present in the oxidation chamber. Additionally, this process requires substantial equipment and piping for circulating and recycling the various gas and liquid streams employed.
U.S. Pat. No. 3,224,837, Peter Moyat, discloses a process for determining organic carbon in water which comprises adjusting pH of an organic containing water sample to the acid range, subjecting said pH adjusted water sample to electrolysis for production of oxygen, oxidizing, with said oxygen, organic carbon present to CO.sub.2, and measuring carbon dioxide content of the gas evolved from such electrolysis step for determining the organic carbon originally present in said water sample. This process requires an acid pH for said water sample to aid electrolysis of water to oxygen and hydrogen, and for releasing carbon dioxide formed by oxidation from solution in said water sample. Consequently, acid for adjusting the water sample pH must be provided, and after determination of the organic carbon content, the acidic water sample must generally be discarded. Further, the electrolysis process of Moyat is not effective for oxidizing refractory organic compounds such as ethanol, acetic acid, amino acids, and fats. Consequently, Moyat provides a catalytic oxidation stage for completing oxidation of such refractory organic compounds in the vapor phase.